US737636A - Extension step-ladder and trestle. - Google Patents

Description

- PATENTED SEPT. 1, 1903. G. LATTA. EXTENSION STEP LADDER AND TRESTLB.

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% f mz v' INVENTOR No. 737,636. PATENTED SEPT. 1, 190a.

0.LATTA. EXTENSION STEP LADDER AND TRESTLE.

. APPLICATION FILED NOV. 13, 1902. N0 MODEL. 2 SHEETS-SHEET 2.

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Patented September 1, 1903.

PATENT OFFICE.

CHARLES LATTA, OF ST. LOUIS, MISSOURI.

EXTENSION STEP-LADDER AND TRESTLE.

SPECIFICATION forming part of Letters Patent N 0. 737,636, dated September 1, 1903. Application filed November 13,1902. Serial No- 13l,109. (No model.)

- T (bZZ whom it may concern:

Be it known that I, OHARLEs LATTA, a citizen of the United States, residing at St. Louis, Missouri, have invented a new and useful Extension Step-Ladder and Trestle, of which the following is a specification.

This invention relates to an extension stepladder and trestle; and'it consists of a novel combination, construction, and arrangement of parts hereinafter shown, described, and claimed.

The object of this invention is to providea device of the class mentioned which may readily be extended to any desired capacity or extent and locked in such position, being permanently and securely held by improved locking devices until manually released, after which it can be restored to its normal position.

In the drawings, Figure 1 is a perspective view of the complete invention. Fig. 2 is a vertical section. Fig. 3 is a perspective of one end of one of the locking devices. Fig. l is a perspective of the lock on the support or the rear side of the ladder. Fig. 5 is the lock for the front portion of the ladder.

The ladder consists of the front portion 1, having the usual steps 2, their ends being mortised in the side members, as shown. The hinge members 3 are rigidly secured to the upper ends of the sides of the front of the ladder, and the rear members of supports 4 have their upper ends pivoted or hinged thereto. The side members 4 are braced or strengthened in their position by the connections 5, rigidly attached thereto in some suitable manner.

The parts just described constitute the stepladder proper; but it may be extended to almost double its normal length by the devices which I will now describe.

Each side member of the front of the ladder is provided on its outer side with a longitudinal groove 6, extending from its upper end to its lower end. The extension members 7 are arranged against the outsides of the side members of the ladder, and attached to their upper ends are the metallic guide members 8, which have integral extensions projecting into the grooves 6, thereby holding the upper ends of the members 7 in position, said members being connected by the cross-pieces 9 in front of the ladder, said cross-pieces serving the function of steps on the extension portion of the ladder.

A guide similar to the extension of the guide 8 is secured for the lower end of each of the'side members of the front of the ladder within the grooves 6, and said guides operate in corresponding grooves 10, formed in the extension members 7.

The rear of the ladder is also provided with an extension member consisting of the sides 11, having guides 12, attached to their upper ends and provided with tongues 13-, which project into grooves 14, formed in the side members 4. Said guides 12 are similar in all respects to the guides 8 and serve a like function. A groove 15 is formed in the inner face in each of the sides 11, and guides 16 are attached in the lower ends of the grooves 14 and project into the said grooves 15, thereby holding the extension portion of the ladder always in position, as is evident. The sides 11 are connected by cross-pieces 17, whereby they are held securely in position.

I provide locks for holding the ladder extended as follows: To each side 1 of the ladder I attach a slide-lock 18 of well-known construction, said lock engaging in openings 19, formed in the steps 9 of the extension portion of the ladder, as clearly shown in Fig. 2. It is manifest that this will securely hold the front portion of the ladder in such adjustment, inasmuch as the steps may be suitably strengthened, if preferred. A series of triangular notches 20 is formed in each of the sides 11, being spaced the same distance apart as the steps on the front of the ladder. A locking member 21 is pivoted to each of the sides 4 and swings outwardly when ongaged, and said members are provided with triangular sections 22, adapted to engage in the triangular notches 20, thereby holding the ladder extended, as is evident.

The front and rear of the ladder are connected by suitable connections 23, which may only be extended a certain number of steps,

the locks being arranged to prevent other adj ustment. This will be found of convenience in determining the height to which the ladder must be extended for use. The locks are simple and are easily released or engaged.

I claim 1. In an extension step-ladder, the combination of supporting and extension frames,

slidable one within the other and provided with matching longitudinal grooves on their adjacent faces said grooves registering with each other and having their open sides juxtaposed, members on each frame projecting into the groove of the other frame, and means for locking the frames where adjusted.

2. In a step-ladder, the combination with supporting and extension frames, and means for preventing relative lateral displacement of said frames, of a fastener for securing the extension-frame where adjusted, comprising notches on one frame, and a pivoted freelyswinging catch on the other frame adapted to engage any of the notches aforesaid, said catch being so pivoted as to be adapted to be swung outwardly from the plane of both of the frames when being released from the notch.

3,. In an extension step-ladder, the combi nation of supporting and extension frames, slidable one within the other and provided with matching longitudinal grooves on their adjacent faces said grooves registering with each other and having their open sides juxtaposed, members on each frame projecting into the groove of the other frame, of a fastener for securing the extension-frame where adjusted, com-prising notches on one frame,

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